The present invention relates to a battery pack manufactured by inserting a part or the whole of a battery into a molded resin portion.
High dimensional accuracy is required for a battery pack. Particularly, high dimensional accuracy is required for the position of an output terminal. The reason is that the output terminal is accurately set to an attachment portion provided in electrical equipment to be connected to a power supply terminal of the electrical equipment so that poor contact does not occur. Currently, a commercially available battery pack has a structure in which a core pack with parts necessary for a battery connected thereto is inserted in an external case formed of plastic. With the battery pack of this structure, forming the external case in an accurate dimension can form the battery pack in prescribed outer dimensions. However, since the battery pack of this structure is assembled by inserting the core pack into the external case with effort, it is difficult to mass-manufacture the battery packs at low cost.
A battery pack which does not employ the external case has been developed in order to achieve a very simple assembly (see Japanese Laid-Open Patent Publication TOKUKAI No. 2000-315483).
This battery pack is manufactured by inserting a part of the core pack with components necessary for a battery connected thereto into a molded resin portion when the molded resin portion corresponding to an external case is molded. With the battery pack of this structure, the core pack is configured by connecting the parts necessary for a battery. This core pack is temporarily held in a molding chamber for molding the molded resin portion. Then, the battery pack is manufactured by injecting molten synthetic resin into the molding chamber. Since this battery pack is fixed when the molded resin portion is molded, it is possible to manufacture the battery pack with efficiency due to the omission of an external case. The molded resin portion composes a part of the external case of the battery pack, and serves to fasten components connected to the battery. Accordingly, since the core pack can be fastened when the molded resin portion is molded, there is a feature that enables the core pack to be manufactured with efficiency at low cost.
With the battery pack of this structure, as shown in FIG. 1, the core pack is inserted into and molded with the molded resin portion used as an external case. With this battery pack, a core pack 90 in which parts necessary for a battery, such as a circuit board 91 connected to a battery 92, are temporarily held in a molding chamber 94 of a metal mold 93. The core pack 90 is inserted by injecting molten plastic into the molding chamber 94 in the state in which a part of the core pack 90 is buried. After the plastic is set, the set plastic is removed from the mold, and thus, the battery pack is manufactured. This battery pack has a structure in which the molded resin portion and the core pack are integrally connected to each other without interstices and the structure can be mass-manufactured.
However, with the battery pack of this structure, since an output terminal separated from the battery pack is connected through a lead wire, there is a disadvantage that this part is manufactured at much expense in time and effort. In addition, with the battery pack of this structure, there is a disadvantage that disconnection of the lead wire or the like can occur. For this reason, in the case of a battery pack used for a cellular phone, for example, the structure in which an output terminal is connected through a lead wire is hardly used. This is because it requires the output terminal to be held at a prescribed position by being inserted into the molded resin portion. However, actually, it is very difficult to mold the molded resin portion with a metal plate as the output terminal must be temporarily and accurately held at the position in the molding chamber of the mold.
The present invention has been developed for solving the above-described disadvantages. It is an important object to provide a battery pack having an output terminal capable of being held at a prescribed position of a molded resin portion with a simple structure, and is capable of being mass-manufactured at low cost.